1. Field of the Invention
The present invention generally relates to medical devices and procedures involving the eye and eye surgery. In particular, the invention relates to medical apparatus, systems and methods for securing tissue during the course of, and after, surgical procedures involving the eye. Still more specifically, the present invention relates to medical apparatus, systems and methods for closing openings in scleral tissue formed during the course of vitreoretinal surgical procedures, and for securing folds formed in scleral tissue.
2. Background
Vitreoretinal surgical procedures for the treatment, or repair, of internal strictures of the eye are well known in the art. For example, the repair of holes or tears in the retina, and the re-attachment of detached retinas, now are fairly common surgical procedures. Similarly, the removal of the vitreous body (the clear, gel-like body that fills the interior of the eye) and its replacement with either another material or a prosthetic device is known. Numerous other examples of surgical procedures of this type will readily occur to those skilled in the art.
Typically, in each of these procedures, a plurality of incisions or "holes" (technically referred to as "sclerotomies") are formed in the sclera to provide access for surgical tools, cannulas and the like to the retina, to the vitreous body and to other internal ocular structures and tissues. Currently, manually placed and tied sutures are utilized both during the course of these surgical procedures, and thereafter. For example, manually placed and tied sutures typically are used for holding infusion cannulas, for securing and/or connecting tissue and otherwise during the surgical procedure, and thereafter to close the sclerotomies.
Manual suturing, however, is an inefficient, time consuming, and skill intensive practice. Further, it is well known that manually placed and tied sutures may tear out of tissue if excessive stress is placed thereon. Accordingly, since the tissue of the eye is subjected to substantial stress during most physical activities performed by a patient, including such simple exertions as coughing or sneezing, alternative apparatus, systems and methods for securing eye tissue would be desirable.
A specific representative example of a vitreoretinal surgical procedure wherein such alternative apparatus, systems and methods would be beneficial is commonly referred to as "Macular Translocation". This vitreoretinal surgical procedure has been recently developed as a substitute for the so-called "Retinal Translocation" procedure wherein the eye is literally disassembled by removal of the lens and the vitreous body, and by detaching the retina for translocation relative to the underlying tissue prior to re-assembly of the eye. These procedures are intended to treat conditions wherein the tissue underlying the macular (central vision) portion of the retina becomes diseased. Degenerative conditions of this sort may result in the photoreceptors of the macula portion of the retina adjacent to the underlying diseased tissue becoming non-functional over time. To avoid this result, the above procedures shift the position of the fovea (i.e., the central portion of the macular portion of the retina which is responsible for a person's sharpest vision) relative to the underlying inner surface of the sclera. This allows the fovea then to be reattached to healthier underlying tissue.
To accomplish this result, the Macular Translocation Procedure, which is less radical than the Retinal Translocation procedure, includes the following steps. First, sutures are placed in a horizontal mattress formation in an arc supero-temporally (i.e., just below the center of the eye, near the ear) on the outer surface of the sclera. These sutures typically are located in the same position relative to the eye regardless of the exact location of the diseased tissue. Then, at least the macula portion of the retina is intentionally detached from the underlying tissue. This usually is accomplished by performing a 3 port pars plana vitrectomy followed by the use of a subretinal infusion cannula and a balanced salt solution to create the desired retinal detachment. The pre-placed sutures are then tightened and tied off. This results in the creation of an inwardly extending fold in the sclera that effectively "shortens" the scleral diameter. Thereafter, an air bubble is formed inside the eye so that the excess length of the retina relative to the shortened underlying scleral surface is moved relative to the diseased tissue. Movement on the order of 1000 microns has been found to be adequate in most cases. Then, a partial air-fluid exchange is made. The natural fluid removal generated by the pigment epithelium and choroid allow the macula portion of the retina, which has been shifted relative to the underlying tissue by the deformation of the sclera and by the formation of the air bubble, to settle against, and reattach itself to, healthy tissue. Finally, several days after the surgical procedure, the diseased lesion is treated with standard laser photocoagulation.
The placement of the sutures in the macular translocation procedure is time consuming and, therefore, inefficient. It is also difficult to consistently predict the distance of scleral shortening that will result upon the tightening and tie off of the sutures. Further, the skill level required to place and to manipulate the sutures without causing extraneous damage to the eye, or surrounding bodily structures, is high.